This invention relates in general to stacking and packaging devices and methods, and more specifically to a novel apparatus and method for automatically stacking rolls of pressure sensitive adhesive tape and interleafing them with a release liner so that the rolls will not adhere to one another when packaged.
In the manufacture of rolls of pressure sensitive adhesive tape, it is well known in the art to slit a web of adhesive coated material into numberous strips of lesser width. The strips are, simultaneous with slitting, wound into rolls of some suitable length of tape, each roll being formed on a separate core carried on a mandrel. As the sides of the rolls may themselves be tacky due to the adhesive which exudes from the roll convolutions, it is common to employ two parallel, spaced apart mandrels as described in U.S. Pat. No. 3,127,123 to Bowker et al., issued Mar. 31, 1964. Adjacent strips are directed from the slitter to different mandrels, thereby spacing the rolls of adhesive tape from one another on each of the mandrels by a distance equal to the width of a single roll. Thus, in the event adhesive is present on the face of the roll, the adhesive faces will not be in contact with one another.
The rolls are then removed from each mandrel and stacked together in some desired number in preparation for packaging. The standard technique is simply to slide or to push the rolls off the mandrel. This results in the rolls coming into face-to-face contact. Where there is an exudate of adhesive, the rolls adhere strongly to one another. As a result, the rolls must then be pried or pulled apart. Heretofore, this separation has been done by hand, usually with the aid of a knife or similar tool. Once separated, the rolls are then stacked by hand and interleafed with paper. These release papers are placed between the adjacent rolls in the stack to prevent them from again adhering to one another during storage in preparation for marketing.
These manual roll separation and stack formation processes have a major disadvantage in that they are extremely slow. In the overall production process, these steps are frequently the limiting factors on production speed. Further, the rolls are frequently damaged when they are pried apart. A common problem is "dishing" or "telescoping" where the inner convolutions of the rolls are pulled out of an overlying alignment with the outer convolutions. This problem is particularly acute in the production of rolls of pressure sensitive tape having a width of 1/4 inch or less. Still further, the use of sharp, hand-held knives and tools needed for separating adjacent rolls adhered together, presents a clear safety hazard.
It is therefore a principal object of this invention to provide an apparatus and method for automatically stacking and interleafing rolls of pressure sensitive adhesive tape initially carried in a spaced relationship on a mandrel whereby the rolls are prevented from adhering to one another.
Another object is to provide a stacking and interleafing apparatus and method that substantially increases production speed and reduces the manufacturing cost of pressure sensitive adhesive tape.